Test F: No Module/Network Communication - ISO 9141 Link
WARNING: This page is about a different car, the 2000 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Depending on module configuration, with all modules connected and with ignition switch in RUN position or with engine running, 2-3 volts may be present at Data Link Connector (DLC) terminal No. 7 (Light Blue/White wire). This is the International Standards Organization (ISO) 9141 diagnostic communications network circuit.
- Turn ignition switch to LOCK position. Inspect NGS tester connector for loose, damaged or corroded terminals. Repair connector as necessary. If connector is okay, disconnect GEM module harness connector C352. Measure resistance in Light Blue/White wire between terminal No. 6 at GEM module harness connector C352 and terminal No. 7 at DLC. See Figure and Figure . If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open in Light Blue/White wire between GEM and DLC.
- Turn ignition switch to RUN position. Measure voltage between terminals No. 7 (Light Blue/White wire) and No. 4 (Black wire) at DLC. See Figure . Also, measure voltage between terminals No. 7 (Light Blue/White wire) and No. 16 (Light Green/Red wire) at DLC. If either measurement indicates zero volts, go to next step. If both measurements indicate voltage, replace GEM.
- Turn ignition switch to LOCK position. Disconnect in-line harness connector C331. See Figure . Turn ignition switch to RUN position. Measure voltage between terminals No. 7 (Light Blue/White wire) and No. 4 (Black wire) at DLC. Also, measure voltage between terminals No. 7 (Light Blue/White wire) and No. 16 (Light Green/Red wire) at DLC. If either measurement indicates zero volts, go to next step. If both measurements indicate voltage, go to step 5 .
- Turn ignition switch to LOCK position. Disable air bag system. See appropriate AIR BAG RESTRAINT SYSTEMS article. Disconnect Restraint Control Module (RCM) harness connector C276. Turn ignition switch to RUN position. Measure voltage between terminals No. 7 (Light Blue/White wire) and No. 4 (Black wire) at DLC. Also, measure voltage between terminals No. 7 (Light Blue/White wire) and No. 16 (Light Green/Red wire) at DLC. If either measurement indicates zero volts, repair short in Light Blue/White wire between DLC, GEM, RCM and in-line harness connector C331. If both measurements indicate voltage, replace RCM.
- Turn ignition switch to LOCK position. Reconnect in-line harness connector C331. If vehicle is equipped with ABS, go to next step. If vehicle is not equipped with ABS, go to step 7 .
- Disconnect ABS module harness connector C141. Turn ignition switch to RUN position. Measure voltage between terminals No. 7 (Light Blue/White wire) and No. 4 (Black wire) at DLC. Also, measure voltage between terminals No. 7 (Light Blue/White wire) and No. 16 (Light Green/Red wire) at DLC. If either measurement indicates zero volts, go to next step. If both measurements indicate voltage, replace ABS control module.
- Turn ignition switch to LOCK position. Disconnect in-line harness connector C107. See Figure . Turn ignition switch to RUN position. Measure voltage between terminals No. 7 (Light Blue/White wire) and No. 4 (Black wire) at DLC. Also, measure voltage between terminals No. 7 (Light Blue/White wire) and No. 16 (Light Green/Red wire) at DLC. If either measurement indicates zero volts, repair short in Light Blue/White wire between in-line harness connector C107 and in-line harness connector C331. If both measurements indicate voltage, repair Light Blue/White wire between in-line harness connector C107 and ABS control module.